1. Field of the Invention
The present invention relates to valves, and more particularly to valves with near zero duty cycle for use in applications such as fuel injection in gas turbine engines.
2. Description of Related Art
A variety of devices are known for metering or checking flow through a system using valves. Traditional valves can be actuated using electrical means, such as linear solenoids, hydraulic means, mechanical means, piezoelectric means, or the like.
Some systems may require multiple valves that can be individually actuated. For example, in gas turbine engines, it is desirable to have individual control for flow to each fuel injector. Since there are typically several fuel injectors in each engine, e.g., twenty or so individual injectors depending on the type of engine, individual injector control requires several individual valves, e.g., about twenty or so. Using traditional valves, difficulties have made impractical the ideal of an individual valve for each injector. The most straightforward actuation means for valves in gas turbine engines are electrical means, such as solenoids. However, given the number of solenoids required, the power requirements using traditional valves are prohibitive. For a system with twenty traditional solenoid valves, in order to maintain all twenty valves in the open position requires a continuous supply of power to each of the twenty solenoids. The power required to hold the twenty solenoids in the open position is actually a considerable amount of the total power generated by the engine itself. Other means of actuation, such as mechanical or hydraulic, introduce complications of their own. For at least the foregoing, it has heretofore been difficult to implement individual injector control in applications like gas turbine engines.
Such conventional methods and systems have generally been considered satisfactory for their intended purpose. However, there is still a need in the art for valves that allow for improved duty cycles. There also remains a need in the art for such valves that are easy to make and use. The present invention provides a solution for these problems.